Blending studies using wheat and lentil cotyledon flour: Effects on rheology and bread quality

Background and objectives
Lentil (Lens Culinaris. Medik) is a highly nutritious food staple widely consumed within India subcontinent and the Mediterranean region. Although gaining popularity in western diets, wheat will continue to be a major crop as it can be used to manufacture a wide range of products. The nutritional benefits of lentils are acknowledged, particularly as a source of high protein so the incorporation of lentil flour into wheat‐based foods has the potential to improve the nutritive value of range food products. Twelve blended flours were made using different concentrations of red lentil cotyledon, wheat, and additional gluten. A blending study was undertaken to access yeast vitality, rheological properties of dough and baking characteristic of resulting bread.

Findings
High ratio blends of lentil flour had no negative effect on yeast vitality even at the highest concentration of 40%. Increasing substitution of lentil flour was highly correlated to increased protein (r = 0.98) and ash (r = 0.95) and a concomitant decrease in dough strength but not extensibility. Loaf volume and baking quality were also compromised at higher concentrations. At a concentration of 5% lentil flour, there were no deleterious effects on dough quality traits or on baking quality. The addition of bakers’ gluten 0.1 g/gram flour had a restorative effect on the rheological and baking characteristics of wheat–lentil composites at higher concentrations of up to 20%.

Conclusions
Our results show that optimal baking quality of wheat–lentil flour can be achieved using either low concentrations of up to 5% lentil flour or up to 20% lentil flour with the addition of gluten which maintained a superior loaf and crumb quality.

Significance and novelty
The protein and ash content of baked breads significantly increased when wheat was partially substituted with lentil flour. The concentration of lentil flour decreased dough strength and dough development time and decreased loaf volume while increasing crumb firmness in resulting bread. The addition of gluten improved the rheological and product quality of bread which allowed higher concentrations of lentil flour to be used in bread making. Balancing the ratio of lentil flour and gluten to optimize the rheological properties will result in a composite wheat–lentil bread with acceptable baking performance and enhanced nutritional benefits for consumers.